How to build a safer text-to-SQL pipeline
Constrain intent, allowlist the schema, separate identifiers from values, enforce read-only access and review execution before text becomes SQL.
Do not send arbitrary prose straight to a database. Convert the request into a small typed intent, resolve every identifier against an authorized schema, build only approved read-only query shapes, bind values separately, enforce limits with read-only credentials, and review the query before execution.
Translate prose into a constrained intent contract
Interpret the request into named fields such as source table, selected columns, filters, sort order and limit. Reject requests that need an unsupported join, aggregate, subquery or write operation instead of carrying the original sentence forward as SQL text.
- Keep the original request for reviewer comparison.
- Return structured ambiguity when a field has more than one meaning.
- Require a limit rather than adding an invisible default after generation.
- Stop when the requested operation falls outside the approved query family.
Resolve identifiers against an authorized schema
Tables and columns cannot be ordinary bind values, so validate them against a server-side schema view that already reflects the user's permissions. Treat model-suggested names, aliases and functions as untrusted until they match the allowlist. Quoting a hostile identifier is not the same as authorizing it.
Construct a query shape instead of concatenating text
Build an abstract query object or a narrow template from validated fields. The generator should choose among permitted clauses, operators and sort directions; it should never splice a raw fragment from the request into SELECT, FROM, WHERE, ORDER BY or LIMIT.
Bind values separately and preserve their order
Turn each filter value into the target driver's placeholder form and send the values through the driver's binding API. Keep the ordered value list beside the review surface. A placeholder protects the value position, but it does not validate a column type, approve data access or make an expensive query cheap.
Enforce read-only execution and operational limits
Run through a least-privileged read-only account, reject multi-statement input, set statement timeouts and result-size ceilings, and log only non-sensitive query metadata. Review representative execution plans and require confirmation when the query can expose sensitive rows or scan a large table.
Check the primary references
Check the source against the result
Show id, status and total cents for paid orders worth at least 1000, newest first, with no more than 50 rows.
Allowed schema: orders(id, status, total_cents, created_at) SELECT id, status, total_cents FROM orders WHERE status = $1 AND total_cents >= $2 ORDER BY created_at DESC LIMIT 50; Bind separately: $1 = paid; $2 = 1000.
The request becomes a declared SELECT shape. Table and columns come from the authorized schema; paid and 1000 remain values rather than SQL syntax; the limit and sort are visible before execution.
Practice the bounded part without a database connection
Use a declared one-table schema and explicit filters to inspect identifier validation, dialect quoting and bind order before execution is even possible.
Open SQL Generator